The link_status array was not large enough to read the Adjust Request Post Cursor2 register. Adjust the size to include it. Found with a -Warray-bounds build:
drivers/gpu/drm/drm_dp_helper.c: In function 'drm_dp_get_adjust_request_post_cursor': drivers/gpu/drm/drm_dp_helper.c:59:27: error: array subscript 10 is outside array bounds of 'const u8[6]' {aka 'const unsigned char[6]'} [-Werror=array-bounds] 59 | return link_status[r - DP_LANE0_1_STATUS]; | ~~~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~ drivers/gpu/drm/drm_dp_helper.c:147:51: note: while referencing 'link_status' 147 | u8 drm_dp_get_adjust_request_post_cursor(const u8 link_status[DP_LINK_STATUS_SIZE], | ~~~~~~~~~^~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
Fixes: 79465e0ffeb9 ("drm/dp: Add helper to get post-cursor adjustments") Signed-off-by: Kees Cook keescook@chromium.org --- include/drm/drm_dp_helper.h | 10 +++++++++- 1 file changed, 9 insertions(+), 1 deletion(-)
diff --git a/include/drm/drm_dp_helper.h b/include/drm/drm_dp_helper.h index 472dac376284..277643d2fe2c 100644 --- a/include/drm/drm_dp_helper.h +++ b/include/drm/drm_dp_helper.h @@ -1517,7 +1517,15 @@ enum drm_dp_phy { #define DP_MST_LOGICAL_PORT_0 8
#define DP_LINK_CONSTANT_N_VALUE 0x8000 -#define DP_LINK_STATUS_SIZE 6 +/* + * DPCD registers in link_status: + * Link Status: 0x202 through 0x204 + * Sink Status: 0x205 + * Adjust Request: 0x206 through 0x207 + * Training Score: 0x208 through 0x20b + * AR Post Cursor2: 0x20c + */ +#define DP_LINK_STATUS_SIZE 11 bool drm_dp_channel_eq_ok(const u8 link_status[DP_LINK_STATUS_SIZE], int lane_count); bool drm_dp_clock_recovery_ok(const u8 link_status[DP_LINK_STATUS_SIZE],